In the Epic Poem Beowulf, Beowulf is described as the typical Epic Hero. Given that Beowulf possess the many characteristics of the Anglo-Saxon hero, he has the ability to defeat the monster Grendel.

Epic heroes, like Beowulf, must possess many different qualities which the society deems great and, therefore, qualifies a man as a hero. This being said, of the many characteristics which make Beowulf a hero, the two characteristics which allow Beowulf to defeat Grendel are 1)the conflict must be with a being of equal or greater ability (no fame comes from defeating a weak opponent) and 2)his decision to fight Grendel without weaponry given Grendel possess and carries no weapons.

In the end, Beowulf takes the arm of Grendel as a trophy, and confirmation, of his vanquishing the beast known for tormenting the people of Hrothgar's kingdom.